Shinaria,
I have experienced Lentas and have seen Loutro so I will tell you what I know about them. Lentas (or Lendas) is a lot lot quieter and smaller than Plakias and more isolated. There are only about 5 or 6 small tavernas (without menus - they tell you what they have cooked today) and a couple of quiet bars in the village. It has a small beach. There are a few places with rooms, but no hotels or apartments with swimming pools.
There is a larger beach over a small headland. This is where the 'far-enders' go. There is camping on the beach and there is a taverna and a small amount of accommodation there.
There is one road out of Lendas that goes over the top of some hills before coming to any other civilisation. There is one bus a day from Iraklion, and it leaves Lendas at 06:30!
I've never stayed in Loutro but I've see it from boats. It is a very pretty village which can only reach by boat - there are no roads. There is only a small beach right in front of the buildings. I think you can walk to Sweetwater beach but it probably takes an hour - this is a "far ender"'s beach.
For something more like Plakias than either of these places, try Matala.
Greecemad.